A woman suspected of murdering 13 patients in a Tuscan hospital in 2014 and 2015 has been arrested, Italian police said in a statement on Thursday.

Called "the hospital ward killer", the woman allegedly committed multiple homicides while working as a nurse in the intensive care and anesthesia ward of a hospital in Piombino, a city on the Tuscan coast.

The nurse's alleged victims had "various pathologies", police said, but no further details about the case were given. Investigators are scheduled to hold a press conference later on Thursday.

Italy's para-military police, the Carabinieri, detained the woman late on Wednesday.

It is not the first time in recent years a nurse working for Italy's state-funded healthcare system has been accused of being a serial killer.

Earlier this month, a court in Ravenna convicted a nurse for killing a patient with a lethal injection of potassium, handing her a life sentence. She is still under investigation for about 10 other suspicious deaths and is appealing last year's conviction.